1. Field of the Invention
This invention relates to a dimorpholinodiethylether having improved isocyanate stability and method for making same. The thus treated dimorpholinodiethylether ("DMDEE") is useful in one component moisture cured systems, for example, polyurethane casting materials and high speed cure sealants. The treated DMDEE of the present invention is also useful polyurethane-based sealant compositions, polyurethane casting materials, in the formation of polyurethane foams and reaction injection molded elastomers.
2. Background Information
Dimorpholinodiethylether ("DMDEE") is widely used in one component moisture cured systems. These systems are isocyanate prepolymers that contain a catalyst, e.g., DMDEE. DMDEE catalyzes the water-isocyanate reaction of the prepolymers upon exposure to water, e.g., moisture in the air or added water. However, to provide adequate shelf life, the catalyst must provide good isocyanate stability to avoid side reactions which gel and harden the prepolymer prematurely. These side reactions are generally branching reactions resulting in biuret and allophanate formation and some formation of isocyanate trimer. Isocyanate stability can be tested by adding a catalyst to toluene diisocyanate and observing the formation of solids. DMDEE, prior to the present invention, was not as stable toward isocyanate as desired.
Accordingly, there is a need to improve the isocyanate stability of DMDEE.